Need help understanding the shell help options
I face very often the problem to understand a syntax of Shell commads help which i usually get usi开发者_JAVA技巧ng options --h or -h or /?
etc. when there are more than 2 or 3 options.
What does this form called? any help docs or links which explain the help syntax are welcome.
whats the difference between [ options ]
and { options }
what does the *
or the |
mean and how do i use it? how important is the order of the options usually? please provide me some good links to documentation about this.
The commands given to a CLI (Command line interface) shell are often in one of the following forms:
- [doSomething] [how] [toFiles]
- [doSomething] [how] [sourceFile] [destinationFile]
- [doSomething] [how] < [inputFile] > [outputFile]
- [doSomething] [how] | [doSomething] [how] | [do Something] [how] > [outputFile]
this was taken from this article guess it doesnt answer exactly the question but its very relevant, take a look at the "Anatomy of a shell CLI"-section.
Here you can find a good documented help with examples for each command.
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